Rinse aids for the machine washing of hard surfaces

ABSTRACT

A process for rinsing hard surfaces comprising contacting the hard surfaces with an aqueous rinse aid composition containing fatty acid-N-alkyl polyhydroxyalkyl amides corresponding to formula I: ##STR1## wherein R 1  CO is an aliphatic acyl radical containing 6 to 22 carbon atoms, R 2  is hydrogen, an alkyl or hydroxyalkyl radical containing 1 to 4 carbon atoms, and  Z! is a linear or branched polyhydroxyalkyl radical containing 3 to 10 carbon atoms and 3 to 10 hydroxyl groups.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to new rinse aids essentially containing fattyacid N-alkyl polyhydroxyalkyl glucamides for the machine washing of hardsurfaces and to the use of these substances for the production of therinse aids.

2. Discussion of Related Art

Commercial rinse aids are mixtures of low-foaming fatty alcoholpolyethylene/polypropylene glycol ethers, solubilizers (for examplecumene sulfonate), organic acids (for example citric acid) and solvents(for example ethanol). The function of rinse aids is to influence theinterfacial tension of the water in such a way that it is able to drainfrom the rinsed surfaces in the form of a thin coherent film, so that nowater droplets, streaks or films remain behind during the subsequentdrying process. A review of the composition of rinse aids and methodsfor testing their performance can be found in W. Schirmer et al. inTens. Surf. Det. 28, 313 (1991).

In addition, where modern phosphate-free low-alkali detergents are usedfor machine dishwashing, lime and silicate coatings can form on therinsed surfaces and on the inside of the dishwashing machine because thecalcium binding power of these detergents is lower than that ofconventional phosphate-containing products. Troublesome lime andsilicate coatings occur in particular when the rinsing water of thedishwashing machine has not been softened sufficiently, if at all, and awater hardness of 4° d is exceeded. In cases such as these, lime andsilicate coatings can be effectively avoided by introducing citric acidinto the final rinse cycle through the rinse aid. However, since thequantities of rinse aid normally added during the final rinse are verysmall (3 ml to 6 ml), the citric acid content in rinse said formulationsintended to guarantee effective inhibition of coatings has to berelatively high to achieve an adequate acid or complexing capacity.Citric acid contents as high as these support the effect of thephosphate substitutes and guarantee spotless dishes.

International patent application WO 88/09369 describes water-basedliquids for dishwashing machines which contain C₈₋₁₆ alkyloligoglucosides, low-foaming fatty alcohol polyglycol ethers and alkalimetal citrates. However, these liquids are unsuitable as rinse aids.

European patent application EP-A2 0 432 836 (Unilever) describes rinseaid formulations for dishwashing machines which contain only onesurfactant, namely alkyl oligoglucosides, and foam inhibitors andthickeners as additional constituents. Foam inhibitors are an essentialconstituent of these formulations because alkyl oligoglucosides aregenerally high foamers and would cause unacceptable foaming in thedescribed rinse aid formulations when used in dishwashing machines.However, defoamers are only effective providing they do not dissolve inthe medium to be foam-inhibited. Accordingly, the alkyl oligoglucosidesolutions and the foam inhibitors are not miscible with one another inthe examples of rinse aids mentioned in this document. Accordingly, twophases would exist if a thickener providing for a certain degree ofhomogenization had not been used to disperse them. However, onedisadvantage of such a formulation is the latent inhomogeneity caused bythe foam inhibitor. The foam inhibitor and surfactant solution of therinse aid separate after only a short time, despite the presence of athickener. A product such as this is understandably unsuitable both forconsumers of branded goods and for large-scale use, because both sectorsrequire products which must remain stable in storage for prolongedperiods, but at least for one year. Accordingly, the only suitableformulations are one-phase formulations in which all the constituentsare homogeneously dissolved and which not only remain stable in storage,but also do not separate during the heating and cooling phase of therinse cycle, i.e. phase stability must be guaranteed in the temperaturerange of the dishwashing machine of 0° C. to 65° C. On the other hand,the known products are so viscous as long as they remain homogeneousthat they cannot be poured in through the rinse aid dispenser of adomestic dishwashing machine.

Various materials (glass, metal, silver, plastic, china) are washed indishwashing machines. These various materials have to be thoroughlywetted in the final rinse cycle. Rinse aids containing alkylpolyglycosides as their only surfactant component satisfy theserequirements to only a limited extent, if at all, so that theclear-rinse or drying effect is unsatisfactory, particularly on plasticsurfaces.

In addition, only those ingredients which are completely biodegradableand toxicologically safe may now be considered for use in detergents,including rinse aid formulations. Particular interest is attached inthis regard to solvent-free products.

Accordingly, the problem addressed by the present invention was toprovide new ecologically and toxicologically safe formulations which, inregard to their performance properties, would give the same results ascommercial rinse aids without having any of their disadvantages.

DESCRIPTION OF THE INVENTION

The present invention relates to rinse aids for the machine washing ofhard surfaces containing fatty acid-N-alkyl polyhydroxyalkyl amidescorresponding to formula (I): ##STR2## in which R¹ CO is an aliphaticacyl radical containing 6 to 22 carbon atoms, R² is hydrogen, an alkylor hydroxyalkyl radical containing 1 to 4 carbon atoms and Z! is alinear or branched polyhydroxyalkyl radical containing 3 to 10 carbonatoms and 3 to 10 hydroxyl groups, and optionally other nonionicsurfactants and typical auxiliaries and additives.

It has surprisingly been found that rinse aids containing fatty acidN-alkyl polyhydroxyalkyl amides and, in particular, fatty acid N-methylglucamides not only show high ecotoxicological compatibility, they alsosatisfy the requirements which a branded product is expected to meet inregard to its performance properties.

Another advantage of the rinse aids according to the invention is thatthe preparation of homogeneous, low-viscosity and hence readilydispensable solutions does not require the use of any other, generallyinert solubilizers which make no contribution to the drying orclear-rinse effect, such as for example sodium cumene sulfonate, ethanolor glucose syrup, except in cases where they are needed in smallquantities for the incorporation of dyes and/or fragrances.

Finally, binary and ternary combinations of the fatty acid N-alkylpolyhydroxyalkyl amides with fatty alcohol polyglycol ethers, mixedethers and/or alkyl oligoglucosides have proved to be particularlyadvantageous. Formulations such as these are extremely low-foaming andwet even different materials equally thoroughly. A particularclear-rinse effect is obtained on plastic surfaces.

Fatty Acid N-alkyl Polyhydroxyalkyl Amides

The fatty acid N-alkyl polyhydroxyalkyl amides are known substanceswhich may normally be obtained by reductive amination of a reducingsugar with ammonia, an alkyl amine or an alkanolamine and subsequentacylation with a fatty acid, a fatty acid alkyl ester or a fatty acidchloride. A relevant synopsis can be found in H. Kelkenberg, Tens. Surf.Det, 25, 8 (1988). Processes for their production are described in U.S.Pat. Nos. 1,985,424, 2,016,962 and 2,703,798, in DE-AS 12 61 861 and inWO 92/06984.

The use of the fatty acid amides mentioned is also the subject of anumber of publications. For example, EP-A10 285 768 (Huls) describestheir use as thickeners. FR-A 1 580 491 (Henkel) describes water-baseddetergent mixtures based on sulfates and/or sulfonates, nonionicsurfactants and optionally soaps which contain fatty acid N-alkylglucamides as foam regulators.

International patent applications WO 92/6153; 6156; 6157; 6158; 6159 and6160 (Procter & Gamble) describe mixtures of fatty acid N-alkylglucamides with anionic surfactants, sulfate and/or sulfonatesurfactants, ether carboxylic acids, ether sulfates, methyl estersulfonates and nonionic surfactants. The use of these substances invarious laundry detergents, dishwashing detergents and cleaning productsis described in WO 92/6152; 6154; 6155; 6161; 6162; 6164; 6170; 6171 and6172 (Procter & Gamble). However, there is no reference in any of thesedocuments to the advantageous use of these substances in rinse aidformulations.

The fatty acid amides to be used in the rinse aid formulations accordingto the invention are preferably derived from reducing sugars containing5 or 6 carbon atoms, more particularly from glucose. Accordingly, thepreferred fatty acid N-alkyl polyhydroxyalkyl amides are fatty acidN-alkyl glucamides corresponding to formula (II): ##STR3##

Fatty acid N-alkyl polyhydroxyalkyl amides corresponding to formula (I),in which R¹ CO is a C₆₋₁₂ acyl radical, R² is a methyl group and is areduced glucose unit, are preferably used as raw materials for theproduction of the rinse aids according to the invention. Accordingly,fatty acid N-methyl glucamides obtained by reductive amination ofglucose with methyl amine and subsequent acylation with a C₆₋₁₂ fattyacid or a corresponding derivative are particularly preferred. So far asthe choice of the fatty acid is concerned, a C₈₋₁₀ fraction of the typeformed, for example, as head fraction in the distillation of technicalcoconut oil fatty acid is particularly suitable.

Nonionic surfactants

Although nonionic surfactants are an optional component of the rinseaids according to the invention, they are nevertheless a preferredcomponent. Basically, any nonionic surfactants may be used for thispurpose although fatty alcohol polyethylene glycol ether, fatty alcoholpolyethylene/polypropylene glycol ether, mixed ethers and/or alkyloligoglucosides are particularly suitable.

Fatty alcohol polyethylene glycol ethers suitable for the purposes ofthe invention correspond to formula (III):

    R.sup.3 O-(CH.sub.2 CH.sub.2 O).sub.n1 H                   (III)

in which R³ is a linear or branched C₆₋₂₂ and preferably C₁₂₋₁₈ alkyland/or alkenyl radical and n1 is a number of 1 to 5.

The substances mentioned are known commercial products. Typical examplesare adducts of, on average, 2 or 4 mol ethylene oxide with technicalC_(12/14) coconut oil fatty alcohol (Dehydol® LS-2 or LS-4, products ofHenkel KGaA) or adducts of, on average, 4 mol ethylene oxide withC_(14/15) oxoalcohols (Dobanol® 45-4, a product of Shell). The productsmay have a conventional or even a narrow-range homolog distribution.

Fatty alcohol polyethylene/polypropylene glycol ethers are understood tobe nonionic surfactants corresponding to formula (IV) ##STR4## in whichR⁴ is a linear or branched C₆₋₂₂ and preferably C₁₂₋₁₈ alkyl and/oralkenyl radical, n2 is a number of 1 to 5 and m2 is a number of 1 to 4.

These substances are also known commercial products. A typical exampleis an adduct of, on average, 5 mol ethylene oxide and 4 mol propyleneoxide with technical C_(12/14) coconut oil fatty alcohol (Dehydol®LS-54, a product of Henkel KGaA).

Mixed ethers are end-capped fatty alcohol polyglycol etherscorresponding to formula (IV): ##STR5## in which R⁵ is a linear orbranched C₅₋₂₂ and preferably C₁₂₋₁₈ alkyl and/or alkenyl radical, n3 isa number of 1 to 10, m2 is 0 or a number of 1 to 4 and R⁶ is a C₁₋₄alkyl radical or a benzyl radical.

Typical examples are mixed ethers corresponding to formula (V), in whichR⁵ is a technical C_(12/14) cocoalkyl radical, n3 is the number 5 or 10,m3 is 0 and R⁶ is a butyl group (Dehypon® LS-54 or LS-104, products ofHenkel KGaA). The use of butyl- or benzyl-terminated mixed ethers isparticularly preferred for applicational reasons.

Alkyl oligoglucosides corresponding to formula (VI):

    R.sup.7 O- G!.sub.p                                        (VI)

in which R⁷ is a C₅₋₁₂ alkyl radical, G is a glucose unit and p is anumber of 1 to 10, are known substances which may be obtained by therelevant methods of preparative organic chemistry. Al 0 301 298 and WO90/3977 are cited as representative of the extensive literatureavailable on this subject.

The alkyl radical R⁷ may be derived from primary alcohols containing 6to 12 and preferably 8 to 10 carbon atoms. Typical examples are caproicalcohol, caprylic alcohol, capric alcohol, undecyl alcohol and laurylalcohol and the technical mixtures thereof which are obtained, forexample, in the hydrogenation of technical fatty acid methyl esters orduring the hydrogenation of aldehydes from Roelen's oxo synthesis. C₈₋₁₀alkyl oligoglucosides (DP=1 to 3), which are obtained as first runningsin the separation of technical C₈₋₁₈ coconut oil fatty alcohol bydistillation and which may contain less than 6% by weight C₁₂ alcohol asan impurity, and alkyl oligoglucosides based on technical oxoalcohols(DP=1 to 3) are preferred.

The index p in general formula (VI) indicates the degree ofoligomerization (DP degree), i.e. the distribution of mono- andoligoglucosides, and is a number of 1 to 10. Whereas p in a givencompound must always be an integer and, above all, may assume a value of1 to 6, the value p for a certain alkyl oligoglucoside is ananalytically determined calculated quantity which is generally a brokennumber. Alkyl oligoglucosides having an average degree ofoligomerization p of 1.1 to 3.0 are preferably used. Alkyloligoglucosides having a degree of oligomerization below 1.7 and, moreparticularly, between 1.2 and 1.4 are preferred from the applicationalpoint of view.

Auxiliaries and Additives

The most important additives are monobasic and polybasic carboxylicacids, preferably hydroxycarboxylic acids. Typical examples are maleicacid (monohydroxysuccinic acid), tartaric acid (dihydroxysuccinic acid);saturated aliphatic dicarboxylic acids, such as oxalic acid, malonicacid, succinic acid, glutaric acid, adipic acid; gluconic acid(hexane-1-pentahydroxycarboxylic acid), although anhydrous citric acidis preferred. They may be used in quantities of from about 1 to 50% byweight and are preferably used in quantities of from about 1 to 30% byweight.

Suitable other additives are, above all, dyes and fragrances.

Rinse Aid Formulations

Typical formulations of the rinse aids according to the invention mayhave the following composition for example (ad 100% by weight water):

0.5 to 20% by weight fatty acid N-alkyl polyhydroxyalkyl amides,

0 to 20% by weight alkyl oligoglucosides,

0 to 20% by weight fatty alcohol polyglycol ethers,

0 to 20% by weight mixed ethers,

1 to 50% by weight carboxylic acid.

Formulations Containing

1 to 10% by weight fatty acid N-alkyl glucamides,

3 to 10% by weight alkyl oligoglucosides,

3 to 10% by weight fatty alcohol polyglycol ethers and/or mixed ethers,

1 to 30% by weight citric acid

are particularly advantageous.

Industrial Applications

The rinse aids according to the invention contain ecotoxicologicallyparticularly safe ingredients, can be formulated without solvents andhave an excellent wetting effect on various materials.

Accordingly, the present invention relates to the use of fatty acidN-alkyl polyhydroxyalkyl amides, more particularly fatty acid N-alkylglucamides, for the production of rinse aids for the machine washing ofhard surfaces, particularly dishes, in which they may be present inquantities of 0.5 to 20% by weight and preferably 1 to 10% by weight,based on the rinse aid as a whole.

The following Examples are intended to illustrate the invention withoutlimiting it in any way.

EXAMPLES

I. Surfactants Used

A1) Octanoic acid N-methyl glucamide

A2) Decanoic acid N-methyl glucamide

A3) C₆₋₁₂ fatty acid N-methyl glucamide

B1) C₈₋₁₀ alkyl oligoglucoside (DP=1.6) Plantaren® APG 225, a product ofHenkel KGaA, Dusseldorf, FRG

C1) C_(12/14) coconut oil fatty alcohol 4EO adduct Dehydol® LS-4, aproduct of Henkel KGaA, Dusseldorf, FRG

C2) C_(12/14) coconut oil fatty alcohol 5EO 4PO adduct Dehydol® LS-54, aproduct of Henkel KGaA, Dusseldorf, FRG

C3) C_(12/14) coconut oil fatty alcohol 10EO butyl ether Dehypon°LS-104, a product of Henkel KGaA, Dusseldorf, FRG.

II. Performance testing of the rinse aids

a) Foaming Behavior:

The foam generation of the rinse aid was determined by means of acirculation pressure gauge. The rinse aid (3 ml) was introduced by handinto the final rinse cycle at 50° C. Foaming was evaluated on thefollowing scale:

0 Points=no foaming

1 Point=slight foaming

2 Points=average foaming (still acceptable)

3 Points=heavy foaming

b) Drying:

15 Minutes after the end of the rinse program, the door of thedishwashing machine was fully opened. After 5 minutes, drying wasdetermined by counting the number of droplets remaining on the articlesof crockery mentioned below. Evaluation was based on the followingscale:

0 Points=more than 5 drops

1 Point=5 drops

2 Points=4 drops

3 Points=3 drops

4 Points=2 drops

5 Points=1 drop

6 Points=0 drops (optimal drying)

c) Clear-rinse effect:

After drying had been evaluated, the articles of crockery were removedfrom the dishwashing machine, left to cool for 30 minutes and thenvisually evaluated under illumination in a black box. The residualdrops, streaks, coatings, cloudy films etc. remaining on the crockeryand cutlery were evaluated. Evaluation:

0 Points=poor clear-rinse effect

8 Points=optimal clear-rinse effect

d) Performance tests b) and c) were carried out in a Bauknecht GSF 1162dishwashing machine using softened water (normal 65° C. program). 40 mlSomat® detergent (Henkel KGaA) were introduced during the wash cycle.The quantity of rinse aid used was 3 ml and was introduced by hand inthe final rinse cycle at 50° C. The water had a salt content of 600 to700 mg/l. Three rinse cycles were carried out for each rinse aidformulation. The following articles of crockery and cutlery were used toevaluate drying and the clear-rinse effect:

∘ 6 "Neckar-Becher" glasses (Schott-Zwiesel)

∘ 3 "Brasilia" stainless steel knives (WMF)

∘ 3 white china plates (Arzberg)

∘ 3 red plastic plates (Haβmann "Valon-Eβteller")

EXAMPLES 1 to 3:

                  TABLE 1                                                         ______________________________________                                        Rinse aids containing fatty acid N-methyl glucamides                          Percentages as % by weight                                                    ad 10% by weight water                                                                       c(A)   CA    FR   St.                                          Ex.   A        %      %     %    °C.                                                                           App. F                                ______________________________________                                        1     A1       15.0   3.0   0.5  >70    Clear                                                                              0                                2     A2       15.0   3.0   0.5  >70    Clear                                                                              0                                3     A3       15.0   3.0   0.5  >70    Clear                                                                              1                                ______________________________________                                         Legend:                                                                       c(A): Concentration of A                                                      CA: Citric acid, anhydrous                                                    FR: Fragrance                                                                 St.: Stability                                                                App.: Appearance of the solution                                              F: Foaming                                                               

EXAMPLES 4 to 6:

                  TABLE 2                                                         ______________________________________                                        Rinse aids containing fatty acid N-methyl glucamides and                      fatty alcohol polyethylene glycol ethers                                      Percentages as % by weight                                                    ad 100% by weight water                                                                  c(Glu)    c(C1)                                                                              CA    FR  St.                                       Ex. Glu    %         %    %     %   °C.                                                                           App. F                             ______________________________________                                        4   A1     9.0       6.0  3.0   0.5 >70    Clear                                                                              0                             5   A2     9.0       6.0  3.0   0.5 >70    Clear                                                                              1                             6   A3     9.0       6.0  3.0   0.5 >70    Clear                                                                              1                             ______________________________________                                    

EXAMPLES 7 to 9:

                  TABLE 3                                                         ______________________________________                                        Rinse aids containing fatty acid N-methyl glucamides and                      fatty alcohol EO/PO adducts                                                   Percentages as % by weight                                                    ad 100% by weight water                                                                  c(Glu)    c(C2)                                                                              CA    FR  St.                                       Ex. Glu    %         %    %     %   °C.                                                                           App. F                             ______________________________________                                        7   A1     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             8   A2     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             9   A3     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             ______________________________________                                    

EXAMPLES 10 to 12:

                  TABLE 4                                                         ______________________________________                                        Rinse aids containing fatty acid N-methyl glucamides and                      mixed ethers                                                                  Percentages as % by weight                                                    ad 100% by weight water                                                                  c(Glu)    c(C3)                                                                              CA    FR  St.                                       Ex. Glu    %         %    %     %   °C.                                                                           App. F                             ______________________________________                                        10  A1     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             11  A2     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             12  A3     9.0       6.0  3.0   0.5 65     Clear                                                                              0                             ______________________________________                                    

EXAMPLES 13 to 16:

                  TABLE 5                                                         ______________________________________                                        Rinse aids containing fatty acid N-methyl glucamides,                         alkyl oligoglucosides and fatty alcohol polyethylene                          glycol ethers                                                                 Percentages as % by weight                                                    ad 100% by weight water                                                                   c(B1)    c(C1)                                                                              CA    FR  St.                                       Ex.  c(A1)  %        %    %     %   °C.                                                                           App. F                             ______________________________________                                        13   7.5    10.7     0    3.0   0.5 >70    Clear                                                                              0                             14   6.0    8.6      3.0  3.0   0.5 >70    Clear                                                                              1                             15   4.5    6.4      3.0  3.0   0.5 >70    Clear                                                                              0                             16   4.0    4.3      3.0  3.0   0.5  60    Clear                                                                              1                             ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Drying of the crockery-cutlery articles/clear-rinse effect                    Formulation                                                                            Glasses       Knives    China     Plastic                            acc. to Ex.                                                                            D     CRE     D   CRE   D   CRE   D   CRE                            ______________________________________                                         1       2.5   6.2     4.2 2.1   5.0 6.4   4.0 5.3                             3       2.9   6.0     4.2 3.1   5.0 6.7   4.2 5.6                             4       4.4   5.8     5.0 4.6   5.0 7.3   5.0 6.7                             5       4.6   6.2     4.7 4.9   5.0 6.7   5.0 6.2                             6       4.2   6.0     4.9 4.4   5.0 6.7   5.0 6.5                             7       4.1   6.0     4.9 6.5   5.1 7.7   5.0 6.8                             8       4.3   6.3     5.0 6.1   5.0 8.0   5.0 7.0                             9       4.6   5.6     4.6 4.9   5.0 7.3   5.0 6.8                            10       4.0   6.1     4.5 6.3   5.1 8.0   5.0 7.0                            11       4.7   6.0     4.4 6.0   5.0 8.0   5.0 7.0                            12       4.8   5.6     4.6 5.2   5.0 7.7   5.0 7.0                            13       2.5   6.1     4.2 4.3   5.0 7.6   3.6 5.8                            14       4.0   5.9     4.6 4.7   5.0 7.9   4.3 5.9                            15       4.5   6.1     4.8 5.8   5.0 7.7   5.0 6.4                            16       4.4   5.9     5.0 6.4   5.0 8.0   5.0 7.0                            C1*      4.8   6.0     4.8 6.6   5.0 8.0   5.0 6.8                            ______________________________________                                         Legend:                                                                       D = Drying                                                                    CRE = Clear rinse effect                                                      C1 = Commercial rinse aid                                                

We claim:
 1. A process for rinsing hard surfaces comprising contactingthe hard surfaces with a rinse aid composition consisting of from 0.5%to 20% by weight of fatty acid-N-alkyl polyhydroxyalkyl amidescorresponding to formula I: ##STR6## wherein R¹ CO is an aliphatic acylradical containing 6 to 22 carbon atoms, R² is an alkyl or hydroxyalkylradical containing 1 to 4 carbon atoms, and Z is a linear or branchedpolyhydroxyalkyl radical containing 3 to 10 carbon atoms and 3to 10hydroxyl groups up to 20% by weight of a nonionic surfactant, 1% to 50%by weight of a carboxylic acid, and the balance being water, based onthe weight of said composition.
 2. The process according to claim 1wherein in formula I, R¹ CO is a C₆₋₁₂ acyl radical, R² is a methylgroup, and Z; is a reduced glucose unit.
 3. The process according toclaim 1 wherein said nonionic surfactant is selected from the groupconsisting of fatty alcohol polyethylene glycol ethers, ethoxylated andpropoxylated fatty alcohol glycol ethers, mixed ethers, alkyloligoglucosides, and mixtures thereof.
 4. A process for making anecologically and toxicologically safe aqueous rinse aid compositioncomprising mixing a composition consisting of from 0.5% to 20% by weightof a fatty acid N-alkyl polyhydroxyalkyl amide corresponding to formulaI: ##STR7## wherein R¹ CO is an aliphatic acyl radical containing 6 to22 carbon atoms, R² is an alkyl or hydroxyalkyl radical containing 1 to4 carbon atoms, and Z is a linear or branched polyhydroxyalkyl radicalcontaining 3 to 10 carbon atoms and 3 to 10 hydroxyl groups, with from1% to 50% by weight of a carboxylic acid, up to 20% by weight of anonionic surfactant, the balance being water, based on the weight ofsaid composition.
 5. The process according to claim 4 wherein in formulaI, R¹ CO is a C₆₋₁₂ acyl radical, R² is a methyl group, and Z is areduced glucose unit.
 6. The process according to claim 4 wherein saidnonionic surfactant is selected from the group consisting of fattyalcohol polyethylene glycol ethers, ethoxylated and propoxylated fattyalcohol glycol ethers, mixed ethers, alkyl oligoglucosides, and mixturesthereof.
 7. The process according to claim 4 wherein said carboxylicacid is selected from the group consisting of monobasic carboxylicacids, polybasic carboxylic acids, saturated aliphatic dicarboxylicacids, and mixtures thereof.
 8. The product of the process of claim 4.9. The product of the process of claim
 5. 10. The product of the processof claim
 5. 11. The product of the process of claim
 16. 12. The productof the process of claim
 7. 13. A process for rinsing hard surfacescomprising contacting the hard surfaces with a rinse aid compositionconsisting of 1% to 10% by weight of fatty acid N-alkyl glucamides, 3%to 10% by weight of alkyl oligoglucosides, 3% to 10% by weight of fattyalcohol polyglycol ethers, 1% to 30% by weight of citric acid, and thebalance, water, based on the weight of said composition.